Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/47—Scattering, i.e. diffuse reflection
  • G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
  • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/44—Detecting, measuring or recording for evaluating the integumentary system, e.g. skin, hair or nails
  • A61B5/441—Skin evaluation, e.g. for skin disorder diagnosis
  • A61B5/443—Evaluating skin constituents, e.g. elastin, melanin, water
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/255—Details, e.g. use of specially adapted sources, lighting or optical systems
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N21/314—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths
  • G01N2021/3144—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths for oxymetry
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N21/314—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths
  • G01N2021/3148—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths using three or more wavelengths
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N21/314—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths
  • G01N2021/317—Special constructive features
  • G01N2021/3177—Use of spatially separated filters in simultaneous way
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N21/314—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths
  • G01N2021/3181—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths using LEDs
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2201/00—Features of devices classified in G01N21/00
  • G01N2201/06—Illumination; Optics
  • G01N2201/062—LED's
  • G01N2201/0627—Use of several LED's for spectral resolution
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2201/00—Features of devices classified in G01N21/00
  • G01N2201/08—Optical fibres; light guides
  • G01N2201/0826—Fibre array at source, distributing

Definitions

• the present invention relates to the an apparatus and method for measuring an analyte, such as a tissue analyte like bilirubin, using light, and, in one particular embodiment relates to estimation of tissue analyte levels in individuals, such as neonates, and more specifically, to an apparatus and method of determining transcutaneous bilirubin (TcB) and estimating total serum bilirubin (TSB) based thereon.
• an analyte such as a tissue analyte like bilirubin
• TcB transcutaneous bilirubin
• TSB total serum bilirubin
• Neonatal jaundice is a yellowing of the skin and other tissues of a newborn infant.
• a bilirubin level of more than 5 mg/dL manifests clinical jaundice in neonates.
• Management of jaundiced neonates typically requires the measurement and monitoring of total serum bilirubin (TSB), which is most commonly determined by analyzing a plasma or serum sample from the infant.
• TBS total serum bilirubin
• the drawing of blood from infants for such an analysis causes pain and trauma. This fact has lead to the development of a number of non-invasive techniques for estimation of TSB.
• TcB transcutaneous bilirubin
• Transcutaneous Bilirubinometry devices work by directing light into the skin of the neonate and detecting specific wavelengths that are reflected back from the neonate's subcutaneous tissues. The number of wavelengths used varies among different devices. The detected optical signals are converted to electrical signals by a photodetector, such as a photodiode, and the electrical signals are analyzed by a controller to generate a TSB value based on the intensity of the reflected signals.
• a white light source is combined with a spectrometer to make the needed measurements. While effective, this solution is more expensive than it needs to be since not all spectral bands are used in the analysis to determine TSB.
• an analyte measuring device for monitoring, for example and without limitation, tissue analyte levels (e.g., bilirubin levels), that includes a number of narrow band light sources, each narrow band light source being structured to emit a spectrum of light covering a number of wavelengths, and a number of detector assemblies configured to receive light reflected from a subject (e.g., the transcutaneous tissues of the subject).
• tissue analyte levels e.g., bilirubin levels
• a subject e.g., the transcutaneous tissues of the subject
• Each of the detector assemblies includes a filter and a photodetector, each filter being structured to transmit a main transmission band and one or more transmission sidebands, wherein for each narrow band light source the spectrum thereof includes one or more wavelengths that fall within the transmission band of at least one of the filters, and wherein for each narrow band light source the spectrum thereof does not include any wavelengths that fall within the one or more transmission sidebands of any of the optical filters.
• a method of estimating level of an analyte such as a tissue analyte (e.g, bilirubin), of a subject, includes steps of directing light from a number of light sources toward the subject (e.g., toward the skin of the subject), each light source emitting a spectrum of light covering a number of wavelengths, wherein in response to the directing, reflected light is reflected by the subject (e.g., the transcutaneous tissues of the subject), filtering the reflected light using a number of filters, each filter being structured to transmit a main transmission band and one or more transmission sidebands, wherein for each light source the spectrum thereof includes one or more wavelengths that fall within the transmission band of at least one of the filters, and wherein for each light source the spectrum thereof does not include any wavelengths that fall within the one or more transmission sidebands of any of the filters, the filtering producing a filtered light associated with each filter, and determining an estimated analyte level, such as
• FIG. 1 is a block diagram of a bilirubin measuring device according to an exemplary embodiment of the present invention
• FIG. 2 is a graph of transmission versus wavelength for an exemplary optical filter that may be employed in the bilirubin measuring device of FIG. 1 ;
• FIG. 3 is a graph of intensity versus wavelength for two narrow band light sources that may be used in a particular embodiment of the bilirubin measuring device of FIG. 1 ;
• FIG. 4 is a graph of transmission versus wavelength for three optical filters that may be employed in a particular embodiment of the bilirubin measuring device of FIG. 1 ;
• FIG. 5 shows the measured effective filter responses based on the filters of FIG. 4 illuminated by the light sources of FIG. 3.
• number shall mean one or an integer greater than one (i.e., a plurality).
• the present invention relates the measurement of analytes, such as, without limitation, tissue analytes like bilirubin, using light analysis, and in particular to an apparatus and method for measuring such analytes.
• tissue analyte is bilirubin.
• the present invention is described in connection with a device for monitoring bilirubin that is able to estimate bilirubin levels using Transcutaneous Bilirubinometry.
• tissue analytes such as, without limitation, oxygen saturation (SpCh), VO2, melanin, and hemoglobin and hemoglobin components like methemoglobin, oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, etc., or other non-tissues analytes such as color pigment.
• SpCh oxygen saturation
• VO2 VO2
• melanin melanin
• hemoglobin and hemoglobin components like methemoglobin, oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, etc.
• other non-tissues analytes such as color pigment.
• FIG. 1 is a block diagram of bilirubin measuring device 5 according to an exemplary embodiment of the present invention.
• Bilirubin measuring device 5 includes a number of narrow band light sources 10, which in the illustrated embodiment are narrow band light source 10A and narrow band light source 10B (while two such narrow band light sources 10 are shown, that is meant to be exemplary only and it will be appreciated that more or less than two narrow band light sources 10 may also be used).
• Each narrow band light source 10A, 10B emits light in a separate transmission band region comprising a selected, limited range of wavelengths.
• Each narrow band light source 10A, 10B is thus not a white light source.
• Each narrow band light source 10A, 10B may be, for example and without limitation, an LED centered at a particular peak wavelength.
• Narrow band light sources 10A, 10B are structured and configured within bilirubin measuring device 5 to transmit light toward the skin of an individual, such as a neonate.
• one or more optical fibers coupled to narrow band light sources 10A, 10B may be used to direct the light toward the skin of the subject.
• Bilirubin measuring device 5 further includes a number of detector assemblies 15, which in the illustrated embodiment are detector assemblies 15A, 15B, 15C (while three such detector assemblies 15 are shown, that is meant to be exemplary only and it will be appreciated that more or less than thee detector assemblies 15 may also be used).
• Detector assemblies 15A, 15B, 15C are each structured to receive and detect light reflected from the subcutaneous tissue of an individual, such as a neonate.
• one or more optical fibers may be coupled to each of the detector assemblies 15A, 15B, 15C to collect and direct the reflected light toward the detector assembly 15A, 15B, 15C.
• Each detector assembly 15A, 15B, 15C is, in the exemplary embodiment, shielded from all light except the light from the narrow band light sources 1 OA, 1 OB that is reflected.
• Each detector assembly 15A, 15B, 15C includes an optical filter 20A, 20B, 20C operatively coupled to (e.g., positioned on top of) an associated photodetector 25A, 25B, 25C.
• Each photodetector 25A, 25B, 25C is a device, such as, without limitation, a photodiode, that converts light into a current or voltage.
• each optical filter 20A, 20B, 20C is a band pass filter that is centered at a predetermined wavelength of light with a predetermined full-width at half maximum (FWHM).
• each optical filter 20A, 20B, 20C is a filter that transmits a main transmission band and one or more transmission sidebands, such as, without limitation, an all-dielectric interference filter stack employing, for example, quarter wavelength mirrors.
• the transmission characteristics of such a filter are shown in FIG. 2, which illustrates a filter having a transmission band centered at 517 nm (with a FWHM of 5 nm) and at least two sidebands. All- dielectric interference filter stacks are advantageous because they have high transmission, good selectivity, and are relatively easy to fabricate on an industrial scale. In an exemplary embodiment, none of the transmission bands overlap one another.
• each narrow band light source 1 OA, 10B emits a spectrum of light that includes light of the center wavelength of one or more of the optical filters 20A, 20B, 20C.
• the emission spectrum of each narrow band light source 1 OA, 10B does not include any light that falls within the transmission sidebands of any of the optical filters 20A, 20B, 20C.
• narrow band light source 10A is a cyan LED centered at about 485 nm and narrow band light source 10B is a green LED centered at about 530 nm.
• the emission characteristics of these light sources are shown in FIG. 3.
• optical filter 20A is an all-dielectric interference filter stack that is centered at 484.22 nm with a FWHM of 5.60714 nm
• optical filter 20B is an all-dielectric interference filter stack that is centered at 517.61 nm with a FWHM of 6.74956 nm
• optical filter 20C is an all- dielectric interference filter stack that is centered at 564.19 nm with a FWHM of 7.35165 nm.
• FIG. 4 shows the measured effective filter responses based on the filters of FIG. 4 illuminated by the light sources of FIG. 3.
• bilirubin measuring device 5 also includes controller 30 that is operatively coupled to narrow band light sources 10A, 10B and detector assemblies 15A, 15B, 15C.
• Controller 30 includes a processing portion which may be, for example, a microprocessor, a microcontroller or some other suitable processing device, and a memory portion that may internal to the processing portion or operatively coupled to the processing portion and that provides a storage medium for data and software executable by the processing portion for controlling the operation of bilirubin measuring device 5, including calculating TcB and/or estimating TSB based on the intensity levels of the light detected by detector assemblies 15A, 15B, 15C.
• bilirubin measuring device 5 is placed against the skin of a subject, such as a neonate. Controller 30 then causes narrow band light sources 10A, 10B to emit and direct light toward the skin of the subject. Light that is reflected from the subcutaneous tissues is filtered by the optical filters 20A, 20B, 20C and detected by the photodetectors 25A, 25B, 25C, which each convert the detected light into an electrical signal (voltage or current). Those electrical signals are then provided to controller 30. Controller 30 will then calculate TcB and/or estimate TSB based on those signals using any of a number of known methodologies. Suitable methodologies are described in, for example, one or more of the following, the disclosures of which are incorporated herein by reference: United States Patent Nos.
• bilirubin measuring device 5 is a fully integrated system, where both narrow band light sources 1 OA, 10B and detector assemblies 15A, 15B, 15C are positioned on the same measurement board, positioned slightly apart from the skin or measurement surface, to allow the light emitted by the narrow band light sources 1 OA, 10B to reflect back from that surface and back-reflect to the detector assemblies 15A, 15B, 15C. Care should be taken to prevent direct light from the narrow band light sources 10A, 10B from hitting the detector assemblies 15A, 15B, 15C. Rather, only reflected light should be permitted to do so.

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Physics & Mathematics (AREA)
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• Veterinary Medicine (AREA)
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• General Physics & Mathematics (AREA)
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• Chemical & Material Sciences (AREA)
• Biochemistry (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Medical Informatics (AREA)
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• Animal Behavior & Ethology (AREA)
• Public Health (AREA)
• Dermatology (AREA)
• Optics & Photonics (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
• Investigating Or Analysing Biological Materials (AREA)

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• 2011
  • 2011-04-27 US US13/697,120 patent/US9279763B2/en not_active Expired - Fee Related
  • 2011-04-27 WO PCT/IB2011/051856 patent/WO2011148280A1/en active Application Filing
  • 2011-04-27 CN CN201180025983.9A patent/CN102906559B/zh not_active Expired - Fee Related
  • 2011-04-27 EP EP11722914.6A patent/EP2577267A1/de not_active Withdrawn

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